Transformer de-rating for high ambient temps, which ANSI C57 standard?
Transformer de-rating for high ambient temps, which ANSI C57 standard?
(OP)
Have done quite a few different searches here, and can't pin down which standard I need to get. I cannot find, in Australia, a standard that guides de-rating factors for higher-than-nameplate ambient temps. That is, if I have a 60 - 65 transformer (oil - winding), that is designed for 40 degree ambient, how much do I de-rate it for use in 50 degree ambient? I realise it won't be 100% accurate, but dpc mentioned in this post ANSI C57, and there are a lot of them.
I don't have access to load / no load losses for the transformer unfortunately, so there isn't any way to be accurate.
It's only a baby (500kVA) but it's always good to add some knowledge that can be extrapolated to other jobs.
Thanks in advance
Mat
I don't have access to load / no load losses for the transformer unfortunately, so there isn't any way to be accurate.
It's only a baby (500kVA) but it's always good to add some knowledge that can be extrapolated to other jobs.
Thanks in advance
Mat






RE: Transformer de-rating for high ambient temps, which ANSI C57 standard?
For ambient conditions other than above, C57.12.91-2011 Loading guide, recommends as below for ambient temperatures from -30C to 50C.
Clause 6.3 &Table 3, for every degree reduction in average ambient temperature the rating can be increased by 1% of kVA rating and for every one degree rise in average ambient temperature, the load shall be decreased by 1.5 % of kVA rating. This is approximate variation in rating and for detailed calculation reference may be made to other clauses in C57.12.91
RE: Transformer de-rating for high ambient temps, which ANSI C57 standard?
Cheers,
Mat
RE: Transformer de-rating for high ambient temps, which ANSI C57 standard?